Pauls thumbies + the 9 speed bar end lever set . It will go Klick for the rear ,
for the indexing , which assumption is, you want.
and the FD gets a universally compatible friction shifter.

cheaper than that , forgo the indexing for both.
then any friction thumb shifter will be fine..

there is some possibility of using a Sram grip shifter ,
but they dont have a friction mode for when the
derailleur adjustments go out of whack.